According to investigators, the incident happened just before 9 p.m. on North Main near Independence Heights Park in northwest Houston.
Officers said the victim was trying to beat the train, but didn't make it and died at the scene.
ABC13 asked Houston police how old the juvenile was, but officers haven't shared that information yet.
Police said the victim was with his cousin and a woman. They did not try to cross the tracks and witnessed everything that occurred, authorities said.
Investigators said the train's engineer saw the victim trying to cross and tried to stop the train.